Technical Field
[0001] The present invention relates to a charger preferred as a vehicle-mounted charger
or the like.
Background Art
[0002] As a vehicle-mounted charger used in an EV (Electric Vehicle) or the like, there
is a vehicle-mounted charger with a configuration such that conversion of power supplied
from an external power supply is implemented, and charging of a storage battery inside
the EV is carried out using direct current voltage obtained as a result of the conversion.
Also, among this kind of vehicle-mounted charger, there is a vehicle-mounted charger
that includes an inverter as means for power conversion.
[0003] This kind of vehicle-mounted charger with a configuration including an inverter is
such that output of the inverter is sometimes stopped suddenly in order to avoid an
occurrence of an electrical shock accident when, for example, a vehicle failure occurs
in charging.
[0004] Therefore, to date, a relay has been interposed between an auxiliary machine power
supply of the vehicle and an internal power supply, which generates power supply voltage
to be supplied to the inverter based on power supply voltage supplied from the auxiliary
machine power supply, and the output of the inverter stopped suddenly by causing the
relay to be turned off. Hereafter, this technology will be referred to as first existing
technology.
[0005] Also, the following technology exists as technology relating to inverter stop control.
In this technology, a gate signal for carrying out switching on and off of an inverter
switching element is transmitted via a photocoupler. When stopping output of the inverter,
a power supply that supplies bias current to a phototransistor of the photocoupler
is turned off, thereby interrupting the supply of the gate signal to the inverter
switching element. In this technology, a circuit that generates the gate signal and
the inverter are linked via the photocoupler, because of which the power supply of
the former and the power supply of the latter can be isolated. Hereafter, this technology
will be referred to as second existing technology. As literature relating to the second
existing technology, there is PTL 1.
Citation List
Patent Literature
Summary of Invention
Technical Problem
[0007] However, in the first existing technology, it is necessary to provide the relay between
the auxiliary machine power supply and the internal power supply, because of which
there is a problem in that the circuit scale increases. Also, in the first existing
technology, the number of parts increases by the number of relays, because of which
there is a problem in that the manufacturing cost increases and the circuit failure
rate increases.
[0008] Also, when causing the output of the charger inverter to be stopped by utilizing
the second existing technology, the following problem occurs. Firstly, a gate drive
circuit, which amplifies the gate signal supplied via the photocoupler to an appropriate
level and supplies the gate signal to each switching element, is provided in the inverter.
When transmission of the gate signal via the photocoupler is interrupted in accordance
with a forced stop signal, input becomes unstable, the gate drive circuit is liable
to oscillate, and there is a possibility that the inverter switching elements will
be erroneously driven.
[0009] The invention, having been contrived in consideration of the heretofore described
situation, has an object of providing a charger such that a power converting inverter
can be reliably stopped in accordance with a forced stop signal, without causing an
increase in part quantity.
Solution to Problem
[0010] The invention provides a charger that generates alternating current voltage using
an inverter and generates direct current voltage for charging a storage battery by
rectifying the alternating current voltage, the charger including a plurality of gate
drive circuits that output a plurality of gate signals for carrying out switching
on and off of a plurality of switching elements configuring the inverter, and a control
power supply that supplies power supply voltage to the plurality of gate drive circuits,
wherein the control power supply includes a transformer, a power supply control circuit
that repeatedly opens and closes a primary side circuit formed by a primary winding
of the transformer and a direct current power supply being connected in series, and
a rectifying circuit that generates power supply voltage to be supplied to the plurality
of gate drive circuits by rectifying alternating current voltage generated in a secondary
winding of the transformer, and the power supply control circuit stops the opening
and closing of the primary side circuit in accordance with a forced stop signal.
[0011] According to the charger, the power supply control circuit stops the opening and
closing of the primary side circuit of the transformer in accordance with the forced
stop signal, because of which the supply of the power supply voltage to the gate drive
circuits from the rectifying circuit connected to the secondary winding of the transformer
is stopped. As a result of this, the supply of the gate signals to the switching elements
configuring the inverter is stopped, whereby charging of the storage battery is stopped.
Advantageous Effects of Invention
[0012] Consequently, according to the invention, a charger such that a power converting
inverter can be reliably stopped in accordance with a forced stop signal, without
causing an increase in part quantity, can be realized.
Brief Description of Drawings
[0013]
[Fig. 1] Fig. 1 is a block diagram showing a configuration of a vehicle-mounted charging
system including a charger according to an embodiment of the invention.
[Fig. 2] Fig. 2 is a circuit diagram showing a configuration of a power conversion
circuit and a control circuit of the charger.
[Fig. 3] Fig. 3 is a circuit diagram showing a configuration of a control power supply
of the charger. Description of Embodiments
[0014] Hereafter, an embodiment of the invention will be described while referring to the
drawings. Fig. 1 is a block diagram showing a configuration of a vehicle-mounted charging
system 1 including a charger 11, which is an embodiment of the invention. The vehicle-mounted
charging system 1 has the charger 11, a junction box 12, a storage battery 13, a BCU
(Battery Control Unit) 14, and a charging connector 16, provided inside an EV. The
junction box 12 carries out a relay of wiring connected to each of the charger 11,
the storage battery 13, and the charging connector 16. The BCU 14 monitors the state
of charge of the storage battery 13. The charging connector 16 is provided in order
to connect a charging plug 18 connected to a quick charger 17a or EVSE (Electric Vehicle
Service Equipment (charging station)) 17b provided on the exterior of the EV to the
EV.
[0015] The charger 11 according to this embodiment has a power conversion circuit 101, an
initial charging circuit 102, and a control circuit 103. Also, the power conversion
circuit 101 has an AC/DC converter 110 and a DC/DC converter 120. The initial charging
circuit 102 is a circuit that, at the start of a charging operation by the charger
11, limits charging current supplied to a capacitor 110_7 provided in the interior
of the AC/DC converter 110 until charging voltage of the capacitor 110_7 rises to
a predetermined voltage value. The control circuit 103 is connected to the initial
charging circuit 102, the AC/DC converter 110, and the DC/DC converter 120, and outputs
a control signal to each circuit. The control circuit 103 and the BCU 14 carry out
a transmission of information using CAN communication via a CAN-BUS 15.
[0016] Fig. 2 is a circuit diagram showing a configuration of the power conversion circuit
101 and the control circuit 103. With regard to the control circuit 103, only a circuit
relating to control of an inverter 121 is shown, in order to prevent the drawing from
becoming complicated. The AC/DC converter 110 is configured with diodes 110_1 and
110_2, freewheel diodes 110_3 and 110_4, FETs 110_5 and 110_6, the capacitor 110_7,
and reactors 110_8 and 110_9. The reactors 110_8 and 110_9 are provided in order to
attenuate high frequency. The diodes 110_1 and 110_2 and the FETs 110_5 and 110_6
configure a rectifying circuit that rectifies alternating current voltage supplied
from the quick charger 17a or the EVSE 17b via the initial charging circuit 102 and
supplies direct current voltage to the capacitor 110_7. The capacitor 110_7 is an
electrolytic capacitor provided in order to smooth the direct current voltage output
from the rectifying circuit. The freewheel diodes 110_3 and 110_6 are connected in
anti-parallel to the FETs 110_5 and 110_6, and cause current generated by electromagnetic
energy accumulated in the reactors 110_8 and 110_9 to flow back to the input power
supply side when switching the FETs 110_5 and 110_6 on and off.
[0017] The DC/DC converter 120 is configured with the inverter 121 and a rectifier 122.
The inverter 121 is configured with FETs 121_5 to 121_8, freewheel diodes 121_1 to
121_4, and a transformer 121_9. The inverter 121 is a circuit that, with the direct
current voltage with which the capacitor 110_7 of the AC/DC converter 110 is charged
as power supply voltage, outputs alternating current voltage to a primary winding
of the transformer 121_9 by switching the power supply voltage using the FETs 121_5
to 121_8. The transformer 121_9 outputs alternating current voltage in accordance
with the alternating current voltage applied to the primary winding to the rectifier
122 from a secondary winding. The rectifier 122 rectifies the alternating current
voltage output from the secondary winding of the transformer 121_9 using diodes 122_1
to 122_4, and supplies direct current voltage to the storage battery 13.
[0018] The control circuit 103 is configured with gate drive circuits 21a to 21d and a
control power supply 3. The gate drive circuits 21a to 21d generate gate signals G1
to G4 having levels appropriate for switching the FETs 121_5 to 121_8 on and off in
accordance with pulse width modulated gate signals g1 to g4 generated by an unshown
gate signal generating unit, and output the gate signals G1 to G4 to the gates of
the FETs 121_5 to 121_8, respectively.
[0019] Fig. 3 is a circuit diagram showing a configuration of the control power supply 3.
The control power supply 3 is a circuit that operates by utilizing input power supply
voltage applied to a power supply input terminal 301, and generates power supply voltage
to be applied to the gate drive circuits 21a to 21d and power supply voltage to be
supplied to another circuit. In this embodiment, an auxiliary machine power supply
is connected to the power supply input terminal 301. The auxiliary machine power supply
is a power supply provided in order to supply power to an auxiliary machine, such
as an air conditioner and a car stereo, of the vehicle in which the vehicle-mounted
charging system 1 is mounted. In this embodiment, a voltage value of the auxiliary
machine power supply is 12V.
[0020] As shown in Fig. 3, the control power supply 3 has a transistor 302, a power supply
control IC 304, a FET 305, a transformer 306, a resistance 307, a capacitor 308, rectifiers
309a to 309c, and a freewheel diode 315.
[0021] The capacitor 308 is interposed between the input power supply terminal 301 and a
ground wire. The capacitor 308 is for removing noise from the power supply voltage
applied to the input power supply terminal 301.
[0022] The transformer 306 has one primary winding 306a and three secondary windings 306b,
306c, and 306d. Herein, one end of the primary winding 306a is connected via the input
power supply terminal 301 to the auxiliary machine power supply, while the other end
of the primary winding 306a is connected to a drain of the FET 305. Further, the source
of the FET 305 is grounded. The freewheel diode 315 is connected in anti-parallel
to the FET 305. In this way, a primary side circuit formed by the auxiliary machine
power supply connected to the input power supply terminal 301, the primary winding
306a of the transformer 306, and the FET 305 being connected in series is formed in
this embodiment. Also, one end of the secondary winding 306b is grounded, while the
other end of the secondary winding 306b is connected to the power supply control IC
304 via the rectifying circuit 309c, which is formed with a capacitor 313c and a diode
314c.
[0023] An emitter of the NPN transistor 302 is grounded, while a collector of the NPN transistor
302 is connected via the resistance 307 to the input power supply terminal 301. The
NPN transistor 302 is switched on and off by an upper ECU (Engine Control Unit) 200
provided inside the vehicle. The upper ECU 200 is connected to a ground wire shared
with the primary side circuit of the transformer 306 in the control power supply 3.
In a period in which no forced stop signal is being generated, the upper ECU 200 turns
the NPN transistor 302 on. Also, when a forced stop signal is generated, the upper
ECU 200 turns the NPN transistor 302 off.
[0024] In a preferred aspect, a forced stop signal is generated in accordance with, for
example, an operation of an operator provided in a charging station on the exterior
of the vehicle, and supplied to the upper ECU 200. In another preferred aspect, a
forced stop signal is generated based on a failure detection signal generated when
a failure of the vehicle, the auxiliary machinery of the vehicle, or the like, is
detected.
[0025] The power supply control IC 304 is an IC having a PWM (Pulse Width Modulation) function,
and is configured with, for example, a microcomputer. The power supply control IC
304 determines whether or not a forced stop signal exists, by comparing collector
voltage of the NPN transistor 302 with a predetermined threshold. Further, at a time
of normal operation when no forced stop signal is being generated, the power supply
control IC 304 cyclically opens and closes the primary side circuit including the
primary winding 306a by applying a pulse train of a constant cycle to a gate of the
FET 305. Thereby, alternating current voltage is output from the secondary windings
306b, 306c, and 306d. The alternating current voltage output from the secondary winding
306b is rectified by the rectifying circuit 309c, and supplied as direct current voltage
to the power supply control IC 304. Further, the power supply control IC 304 controls
a pulse width of the pulse train supplied to the FET 305 so that the direct current
voltage supplied via the rectifying circuit 309c reaches a predetermined target value.
[0026] Also, when detecting the generation of a forced stop signal based on the collector
voltage of the NPN transistor 302, the power supply control IC 304 stops the supply
of the pulse train to the gate of the FET 305 to forcibly turn the FET 305 off. Thereby,
the primary side circuit including the primary winding 306a switches to an open state,
and the output of alternating current voltage from the secondary windings 306b, 306c,
and 306d is stopped.
[0027] The rectifier 309a is configured with a capacitor 313a and a diode 314a, and rectifies
the alternating current voltage output from the secondary winding 306c of the transformer
306, thereby converting the alternating current voltage to direct current voltage.
In the same way, the rectifier 309b is configured with a capacitor 313b and a diode
314b, and rectifies the alternating current voltage output from the secondary winding
306d of the transformer 306, thereby converting the alternating current voltage to
direct current voltage. Voltage output from the rectifying circuit 309a is supplied
as power supply voltage to the gate drive circuits 21a to 21d, and voltage output
from the rectifying circuit 309b is supplied as power supply voltage to a circuit
other than the gate drive circuits 21a to 21d.
[0028] Hereafter, a description will be given of an operation of the vehicle-mounted charging
system 1 including the charger 11 according to this embodiment. In Fig. 1, an operator
connects the charging plug 18 connected to the quick charger 17a or the EVSE 17b to
the EV charging connector 16 in order to carry out charging of the storage battery
13. At this time, an instruction to start charging is transmitted from the EV, and
charging of the storage battery 13 is started under monitoring of the state of charge
and discharge by the BCU 14. Alternating current voltage output from the quick charger
17a or the like is input via the charging connector 16 to the charger 11.
[0029] The alternating current voltage input to the charger 11 is applied to the AC/DC converter
110 via the initial charging circuit 102 shown in Fig. 2. The alternating current
voltage that has passed through the initial charging circuit 102 is rectified by the
AC/DC converter 110, and the capacitor 110_7 is charged by direct current voltage
obtained as a result of the rectification.
[0030] The direct current voltage with which the capacitor 110_7 of the AC/DC converter
110 is charged is applied as power supply voltage to the inverter 121. The gate signals
G1 to G4 are applied to the FETs 121_5, 121_6, 121_7, and 121_8 of the inverter 121
from the gate drive circuits 21a to 21d respectively. To describe in further detail,
the gate drive circuits 21a to 21d cause the pair of FETs 121_5 and 121_8 and the
pair of FETs 121_7 and 121_6 to be turned on alternately by causing the gate signals
G1 to G4 to vary, thereby causing alternating current voltage to be output to the
primary winding of the transformer 121_9.
[0031] Thereby, alternating current voltage is generated in the secondary winding of the
transformer 121_9. The alternating current voltage of the secondary winding is rectified
by the rectifier 122, thus being converted into direct current voltage. The direct
current voltage is output to the storage battery 13 via the junction box 12 shown
in Fig. 1, whereby the storage battery 13 is charged.
[0032] In Fig. 3, the transistor 302 is in an on-state when no forced stop signal is being
generated. Therefore, the power supply control IC 304 outputs a pulse train that causes
the FET 305 to be turned on and off. Thereby, alternating current voltage is applied
to the primary winding 306a of the transformer 306, and alternating current voltage
is output from the secondary windings 306b, 306c, and 306d of the transformer 306.
The alternating current voltages output from the secondary windings 306c and 306d
are rectified by the rectifying circuits 309a and 309b, whereby each is converted
into direct current voltage. The direct current voltage output from the rectifying
circuit 309a is supplied as power supply voltage to the gate drive circuits 21a to
21d.
[0033] When a forced stop signal is generated, the upper ECU 200 turns the transistor 302
off. As a result of this, the power supply control IC 304 stops the output of the
pulse train to the gate of the FET 305, thereby forcibly turning the FET 305 off.
As a result of this, no alternating current voltage is applied to the primary winding
306a of the transformer 306, and the output of alternating current voltage from the
secondary windings 306b, 306c, and 306d of the transformer 306 is stopped. Therefore,
the rectifying circuit 309a stops the supply of power supply voltage to the gate drive
circuits 21a to 21d. When the supply of power supply voltage is stopped, the gate
drive circuits 21a to 21d stop the output of the gate signals G1 to G4, whereby all
of the FETs 121_5 to 121_8 of the inverter 121 are turned off. As a result of this,
the application of alternating current voltage to the transformer 121_9 is stopped,
whereby the output of voltage from the rectifier 122 on the secondary side of the
transformer 121_9 is stopped. Further, the charging of the storage battery 13 is stopped.
[0034] According to the heretofore described embodiment, the following advantages are obtained.
[0035] Firstly, in the heretofore described first existing technology, it is necessary to
provide a relay between the input power supply terminal 301 and auxiliary machine
power supply in this embodiment. Therefore, there is a problem in that the charger
circuit scale increases. Also, as the number of parts increases by the number of relays,
there is a problem in that the manufacturing cost increases and the circuit failure
rate increases.
[0036] As opposed to this, this embodiment is such that the relay necessary in the first
existing technology is unnecessary. Therefore, the problem occurring in the first
existing technology does not occur.
[0037] Also, in the second existing technology, the gate signals g1 to g4 in this embodiment
are supplied to the inverter 121 via a photocoupler. Herein, when transmission of
the gate signals via the photocoupler is interrupted in accordance with a forced stop
signal, the power supply remains connected to the gate drive circuits, because of
which input becomes unstable, the gate drive circuits oscillate, and there is a possibility
that the inverter switching elements will be erroneously driven.
[0038] As opposed to this, this embodiment is such that the power supply control IC 304
forcibly switches the primary side circuit of the transformer 306, which is the source
of supplying power supply voltage to the gate drive circuits 21a to 21d, to an open
state in accordance with a forced stop signal, because of which the operation of the
gate drive circuits 21a to 21d can be reliably stopped, and charging of the storage
battery 13 can be reliably stopped.
[0039] Furthermore, this embodiment is such that the power supply control IC 304 and the
upper ECU 200 that transmits a forced stop signal to the power supply control IC 304
are connected to a shared ground wire. Consequently, there is no need to interpose
an element such as a photocoupler for insulation in this path. Consequently, there
is no need to provide an element for insulation, such as a photocoupler, in a forced
stop signal transmission path between the upper ECU 200 and the power supply control
IC 304. Consequently, the manufacturing cost of the charger 11 can be reduced.
(Other Embodiments)
[0040] Heretofore, an embodiment of the invention has been described, but other embodiments
of the invention are conceivable. Examples are as follows.
- (1) In the heretofore described embodiment, a relay may be interposed between the
input power supply terminal 301 and the auxiliary machine power supply. By so doing,
duplication of the charge stopping function can be achieved, and charging can more
reliably be stopped.
- (2) The charger in the heretofore described embodiment is applicable not only to a
vehicle-mounted charger, but also to a railroad car-mounted or aircraft-mounted charger.
- (3) In the heretofore described embodiment, a forced stop signal may be generated
when any of multiple kinds of events occurs.
Reference Signs List
[0041] 1 ... Vehicle-mounted charging system, 11 ... Charger, 101 ... Power conversion circuit,
102 ... Initial charging circuit, 103 ... Control circuit, 110 ... AC/DC converter,
110_5, 110_6, 121_5, 121_6, 121_7, 121_8, 305 ... FET, 110_7, 308, 313a, 313b, 313c
... Capacitor, 110_3, 110_4, 121_1, 121_2, 121_3, 121_4, 315 ... Freewheel diode,
110_1, 110_2, 122_1, 122_2, 122_3, 122_4, 314a, 314b, 314c ... Diode, 110_8, 110_9...
Reactor, 121_9, 306 ... Transformer, 120 ... DC/DC converter, 121 ... Inverter, 12
... Junction box, 13 ... Storage battery, 14 ... BCU, 15 ... CAN-BUS, 16 ... Charging
connector, 17a ... Quick charger, 17b ... EVSE, 18 ... Charging plug, 21_a, 21_b,
21_c, 21_d ... Gate drive circuit, g1, g2, g3, g4, G1, G2, G3, G4 ... Gate signal,
3 ... Control power supply, 301 ... Input power supply terminal, 302 ... Transistor,
200 ... upper ECU, 304 ... Power supply control IC, 307 ... Resistance, 309a, 309b,
309c ... Rectifier.